The driver of a train that derailed in northwestern Spain last week, killing 79 people, was on the phone with railway staff when the train crashed, court officials announced Tuesday, citing information from data recorders.

The train was going 153 kph (95 mph) when it derailed, the superior tribunal of Galicia said.

That's nearly twice the speed limit on the curve where the accident happened.

Authorities have charged the train's driver, Francisco Jose Garzon, with 79 counts of homicide by professional recklessness and an undetermined number of counts of causing injury by professional recklessness.

A court has granted Garzon conditional release, but his license to operate a train has been suspended for six months. He also was required to surrender his passport and report to court weekly. CNN efforts to locate him have been unsuccessful.

The train, nearing the end of a six-hour trip between Madrid and Ferrol, derailed Wednesday evening as it hurtled around a bend in Santiago de Compostela.

Minutes before the derailment, Garzon received a call on his work phone, apparently receiving instructions on the way to Ferrol from a Renfe staff member, the court said Tuesday. Background noise suggested he was looking at or shuffling papers, the court said.

JUST WATCHED

Deadly high-speed-train crash

MUST WATCH

Deadly high-speed-train crash00:45

PLAY VIDEO

Photos: Spanish train crash aftermath 10 photos

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – Spain's Princess Elena, left, Princess Letizia and Prince Felipe attend a funeral Mass for the victims of a train derailment at a cathedral in Santiago de Compostela on Monday July 29. At least 79 people have been confirmed dead in the July 24 crash in northwest Spain.

Hide Caption

1 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – Prince Felipe expresses his condolences to a family of the victims of the train accident during the funeral July 29.

Hide Caption

2 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – A woman kneels on July 29 in the cathedral.

Hide Caption

3 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – People carry the coffin of a victim in Ciudad Real, Spain, on July 29.

Hide Caption

4 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – A woman prays at the main gate of Santiago de Compostela Cathedral on Sunday, July 28. The crash occurred on the eve of a public holiday, when more people than usual may have been traveling in the region.

Hide Caption

5 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – A man and child survey a memorial including a Galician flag on July 28.

Hide Caption

6 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – Eighteen-year-old Stephen Ward rests outside a church in Madrid on Saturday, July 27. Ward, from Utah, was among the survivors of the deadly train crash.

Hide Caption

7 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – People carry the coffin of a victim at the San Pedro de Visma cemetery in A Coruna, Spain, on July 27.

Hide Caption

8 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – A man leaves his cane next to candles in memory of the train crash victims on Friday, July 26, in Santiago de Compostela.

Hide Caption

9 of 10

Photos: Spanish train crash aftermath10 photos

Spanish train crash aftermath – A woman looks over the scene from a bridge on July 26.

Hide Caption

10 of 10

EXPAND GALLERY

Photos: Deadly train crash in Spain 26 photos

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Wreckage of the front locomotive of a derailed train stands on the road while workers repair the railway on Sunday, July 28, in Santiago de Compostela, Spain. A spokeswoman for the Galician regional government said that at least 79 people were confirmed dead in the train crash. It occurred on the eve of a public holiday, when more people than usual may have been traveling in the region.

Hide Caption

1 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Train driver Francisco Jose Garzon is taken from a police station to the Preliminary Court in Santiago de Compostela on July 28.

Hide Caption

2 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Spanish Prime Minister Mariano Rajoy, second from left, and Galicia's regional President Alberto Nunez Feijoo, right, visit the site of the derailment on Friday, July 26.

Hide Caption

3 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Injured people are evacuated at the site of the July 24 train accident. The driver of the train is being held, Spanish police said July 26.

Hide Caption

4 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – A train car is lifted Thursday, July 25, at Angrois near Santiago de Compostela, Spain. The train derailed as it hurtled around a curve at high speed on Wednesday, July 24.

Hide Caption

5 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Emergency personnel work at the crash scene July 25. An investigation into the cause of the derailment is under way.

Hide Caption

6 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Spanish Prime Minister Mariano Rajoy, center, visits the crash site July 25 with Public Works Minister Ana Pastor, right, and Alberto Nunez Feijoo, head of the regional government in Galicia. The latter declared seven days of mourning for victims of the crash.

Hide Caption

7 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – A relative of one of the passengers waits to hear news in Santiago de Compostela on July 25.

Hide Caption

8 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Other relatives of passengers wait for information in Santiago de Compostela on July 25.

Hide Caption

9 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Rescue workers inspect a carriage in the wreckage July 25.

Hide Caption

10 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – A general view of the derailment in northwestern Spain on July 25.

Deadly train crash in Spain – The state railway company said the train derailed on a curve as it was approaching the train station in Santiago de Compostela.

Hide Caption

19 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Emergency workers climb on top of the wreckage as they help free injured passengers from the crash.

Hide Caption

20 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – While it was unclear how fast the train was going at the time of the crash, it was capable of reaching up to 155 mph.

Hide Caption

21 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Rescuers work to pull victims from the derailed cars.

Hide Caption

22 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – One person at the scene said he saw several passengers and witnesses helping get people out of the mangled cars.

Hide Caption

23 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Rescuers work to clear a derailed car.

Hide Caption

24 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – "The efforts now center on searching for bodies and victims that could still be alive in the wreckage of the cars," journalist Ignacio Carballo from the Voz de Galicia newspaper told CNN en Español.

Hide Caption

25 of 26

Photos: Deadly train crash in Spain26 photos

Deadly train crash in Spain – Officials said blood donations were needed as a result of the crash.

Hide Caption

26 of 26

EXPAND GALLERY

JUST WATCHED

Pilgrims mourn Spain train crash victims

MUST WATCH

Pilgrims mourn Spain train crash victims02:02

PLAY VIDEO

On Spain's railroad system, command and control posts can communicate with drivers at any point during a journey, a spokeswoman from Renfe -- the Spanish railroad company -- told CNN's Karl Penhaul. Drivers communicate via radio-telephones known in Spanish as "tren-tierras" or train-to-land. But drivers also use mobile phones if radio-telephones are not working or "when it's considered necessary," the spokeswoman said.

Steve Harrod, a railroad transportation expert at Ohio's University of Dayton, said he was stunned by the report that the driver may have been speaking on the phone shortly before the crash. In the United States, Harrod said, railroad drivers are not allowed to use cell phones to prevent dangerous distractions.

Shortly before the train crashed, according to reports, the Spanish train had passed from a computer-controlled area of the track to a zone that requires the driver to take control of braking and acceleration, Harrod said. "It's possible that the driver's phone conversation -- which apparently was part of his official capacity as a driver -- distracted him and he missed the transition from automatic to driver control," Harrod said. He may have been unaware he was in control of the train and realized, 'oh, no, we're headed for a curve.' If that's true, I really don't think it was his fault."

The Renfe spokeswoman told CNN that command and control posts have real-time systems to show each train's precise location at a given time. If this were the case, a controller who would have phoned the train driver might have known the train was approaching a curve.

According to an interview in state-owned Efe news service with the president of the state-owned Administrator of Railway Infrastructures, the train should have started slowing down about 4 kilometers (2.48 miles) before the curve. At 192 kph, the train would have been traveling about 3.2 kilometers a minute.

He hit the brakes seconds before the crash, bringing the speed down from 192 kph (119 mph), according to the court. He was still on the phone when the train flew off the tracks.

Of the 79 who died in the ensuing wreck, 63 were from Spain. Others were from the United States, Latin America and Europe.

The victims were remembered Monday in a memorial Mass at a Catholic cathedral in Santiago de Compostela.

"Our brothers lost their lives ... when they had so many plans," said Archbishop Julian Barrio." It is not easy to understand and accept this reality," he said, "but I say to you, let our pain not be wasted. Everything has meaning in our lives. We are not shouting in a vacuum."